The thermoelectric power (TEP) and the electrical resistivity (ER) of Al-Mg-Si (balanced) and Al-Mg-Si-Cu (balanced + Cu) alloys have been measured in the temperature range 300-800 K. TEP and ER are found affected by different types of precipitates in the Al matrix. Addition of Cu refined the microstructure of the balanced alloy hence altered the TEP and ER measurements. Cu promotes the kinetics of artificial aging due to the formation of the Q' phase and the intermediate phases which precipitate at earlier temperatures. The coexistence of the equilibrium (3 (Mg2Si) and the stable Q-phases results in stabilization of the TEP at elevated temperatures. The existence of Cu slightly increases the lattice rigidity leading to a decrease in the rate by which the ER increases with temperature. Repeating measurements after slow cooling of the two alloys changed considerably the results of TEP and ER. Correlation was found between different types of precipitates and changes in the TEP and ER indicating the possibility of employing TEP and ER measurements to study the precipitation sequence in such alloys.

The thermoelectric power (TEP) and the electrical resistivity (ER) of Al-Mg-Si (balanced) and Al-Mg-Si-Cu (balanced + Cu) alloys have been measured in the temperature range 300-800 K. TEP and ER are found affected by different types of precipitates in the Al matrix. Addition of Cu refined the microstructure of the balanced alloy hence altered the TEP and ER measurements. Cu promotes the kinetics of artificial aging due to the formation of the Q' phase and the intermediate phases which precipitate at earlier temperatures. The coexistence of the equilibrium (3 (Mg2Si) and the stable Q-phases results in stabilization of the TEP at elevated temperatures. The existence of Cu slightly increases the lattice rigidity leading to a decrease in the rate by which the ER increases with temperature. Repeating measurements after slow cooling of the two alloys changed considerably the results of TEP and ER. Correlation was found between different types of precipitates and changes in the TEP and ER indicating the possibility of employing TEP and ER measurements to study the precipitation sequence in such alloys.

The thermoelectric power (TEP) and the electrical resistivity (ER) of Al-Mg-Si (balanced) and Al-Mg-Si-Cu (balanced + Cu) alloys have been measured in the temperature range 300-800 K. TEP and ER are found affected by different types of precipitates in the Al matrix. Addition of Cu refined the microstructure of the balanced alloy hence altered the TEP and ER measurements. Cu promotes the kinetics of artificial aging due to the formation of the Q' phase and the intermediate phases which precipitate at earlier temperatures. The coexistence of the equilibrium (3 (Mg2Si) and the stable Q-phases results in stabilization of the TEP at elevated temperatures. The existence of Cu slightly increases the lattice rigidity leading to a decrease in the rate by which the ER increases with temperature. Repeating measurements after slow cooling of the two alloys changed considerably the results of TEP and ER. Correlation was found between different types of precipitates and changes in the TEP and ER indicating the possibility of employing TEP and ER measurements to study the precipitation sequence in such alloys.

The thermoelectric power (TEP) and the electrical resistivity (ER) of Al-Mg-Si (balanced) and Al-Mg-Si-Cu (balanced + Cu) alloys have been measured in the temperature range 300-800 K. TEP and ER are found affected by different types of precipitates in the Al matrix. Addition of Cu refined the microstructure of the balanced alloy hence altered the TEP and ER measurements. Cu promotes the kinetics of artificial aging due to the formation of the Q' phase and the intermediate phases which precipitate at earlier temperatures. The coexistence of the equilibrium (3 (Mg2Si) and the stable Q-phases results in stabilization of the TEP at elevated temperatures. The existence of Cu slightly increases the lattice rigidity leading to a decrease in the rate by which the ER increases with temperature. Repeating measurements after slow cooling of the two alloys changed considerably the results of TEP and ER. Correlation was found between different types of precipitates and changes in the TEP and ER indicating the possibility of employing TEP and ER measurements to study the precipitation sequence in such alloys.

optical absorption measurements are carrird out on as-deposited and thermal annealed SeTeSbfilms. the annealed films show an increase in the optical enerergy gap with increasing temp. of annealing.

In this paper, the effects of variable viscosity and thermal conductivity on coupled heat and mass transfer by free convection about a permeable horizontal cylinder embedded in porous media using Ergun mode are studied. The fluid viscosity and thermal conductivity and are assumed to vary as a linear function of temperature while the mass diffusion is assumed to vary as linear function of concentration. The surface of the horizontal cylinder is maintained at a uniform wall temperature and a uniform wall concentration. The transformed governing equations are obtained and solved by using the implicit finite difference method. Numerical results for dimensionless temperature and concentration profiles as well as Nusselt and Sherwood numbers are presented for various values of parameters namely, Ergun number, transpiration parameter, Rayleigh and Lewis numbers and buoyancy ratio parameter.

The unsteady mixed convection boundary layer flow near the stagnation point on a heated vertical plate embedded in a fluid saturated porous medium is studied. It is assumed that the unsteadiness is caused by the impulsive motion of the free stream velocity and by sudden increase in the surface temperature. Both the buoyancy assisting and the buoyancy opposing flow situations are considered with combined effects of the first and second order resistance of solid matrix of non-Darcy porous medium, variable viscosity and radiation. The problem is reduced to a system of non-dimensional partial differential equations, which is solved numerically using the Keller-box method. The features of the flow and the heat transfer characteristics for different values of the governing parameters are analyzed and discussed. The surface shear stress and the heat transfer of the present study are compared with the available results and a good agreement is found.

Analytical descriptions of the geometric phases (GPs) for the total system and subsystems are studied for a current biased Josephson phase qubit strongly coupled to a lossy LC circuit in the dispersive limit. It is found that, the GP and purity depend on the damping parameter which leads to the phenomenon of GP death. Coherence parameter delays the phenomenon of a regular sequence of deaths and births of the GP. The asymptotic behavior of the GP and the purity for the qubit-LC resonator state closely follow that for the qubit state, but however, for the LC circuit these asymptotic values are equal to zero.

In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0–7.0, initial metal concentration 0.0–300 mg/L and contact time 0–120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r2  0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions.

In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0–7.0, initial metal concentration 0.0–300 mg/L and contact time 0–120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r2  0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions.